Contact probe

ABSTRACT

A contact probe is fabricated by forming a resin mold with a cavity on a substrate having conductivity, and filling the cavity with metal through electroforming. The metal includes a cobalt-tungsten alloy. Alternatively, a cobalt-molybdenum alloy may be used instead of the cobalt-tungsten alloy. Alternatively, a contact probe can be made from nickel, cobalt or copper, and have a coat film of cobalt-tungsten alloy or cobalt-molybdenum alloy formed thereon to increase the abrasion resistance. A nickel-molybdenum alloy can be used instead of the cobalt-tungsten alloy or cobalt-molybdenum alloy.

TECHNICAL FIELD

[0001] The present invention relates to a contact probe to performelectrical testing on a semiconductor IC chip, a liquid crystal displaydevice, and the like.

BACKGROUND ART

[0002] Electrical testing on a circuit formed on a semiconductorsubstrate, a liquid crystal device, and the like is conducted using atester formed of a probe card having a plurality of contact probesdisposed corresponding to the arrangement of the circuit to be tested.

[0003] A contact probe requires a leading end with contact capabilityand a spring with urging capability to ensure the contact with thepattern interconnection that is the subject of testing without damagingthe interconnection and that allows repetitive usage.

[0004] These elements are conventionally configured with a combinationof individual components thereof. Fabrication of a contact probe formedintegrally by electroforming is disclosed in, for example, JapanesePatent Laying-Open Nos. 2000-162241 and 11-337575. Such contact probesallow the usage of copper, nickel, aluminum, rhodium, palladium,tungsten, a nickel-cobalt alloy, and the like as the electroformingmaterial.

[0005] Japanese Patent Laying-Open No. 9-34286 discloses the techniqueof forming a fixation belt using, as the substrate, an endlesselectroforming sheet made from a nickel-manganese alloy containing0.05-0.6 wt % manganese and having a Micro-Vickers hardness of 450-650to provide a fixation belt for a photolithography apparatus having highthermal conductivity and rigidity as well as superior heat resistanceand fatigue resistance.

[0006] Japanese Patent Laying-Open No. 11-44708 discloses a contactprobe having a plurality of pattern interconnections formed on a filmwith the tip protruding therefrom, using a nickel-manganese alloy as thematerial. This contact probe is composed of a first metal layer formedof a nickel-manganese alloy containing at least 0.05% by weightmanganese, and a second metal layer having toughness and conductivityhigher than those of the first metal layer. The contact probe has thesecond metal layer bent outwards partially. The publication teaches thatsuch a contact probe has high hardness and high mechanical strength toallow repetitive usage.

[0007] For a contact probe, hardness, elasticity, and abrasionresistance are required as a contact that can be repeatedly used bybeing urged against a circuit to be tested. The contact probe must alsobe heat resistant to exhibit sufficient performance even when used underhigh temperature for application to burn-in testing. In accordance withthe techniques disclosed in the aforementioned two publications,selection of the component of the alloy to improve the hardness and heatresistance, coverage by means of different types of material, andmicroscopic configurations have been employed. However, the hardness ofthe electroforming material was only 600-700 at most in Micro-Vickershardness. The abrasion resistance was still not sufficient in view ofrepetitive scribing that will be conducted as a contact probe.

[0008] Thus, there is a limit in improving the hardness of a contactprobe formed in one piece by means of electroforming since the hardnessof the material of the substrate itself is limited. The need arises fora contact probe that can exhibit sufficient performance in all theaspects of hardness, elasticity, abrasion resistance, and heatresistance.

DISCLOSURE OF THE INVENTION

[0009] An object of the present invention is to provide a contact probesuperior in all the aspects of hardness, elasticity, abrasionresistance, and heat resistance.

[0010] To achieve the above object, a contact probe according to anaspect of the present invention is fabricated by forming a resin mold ona substrate having conductivity, and filling the cavity of the resinmold with metal through electroforming. The metal is a nickel-manganesealloy. The average crystal grain size of nickel is not more than 70 nm.The contact probe is formed of a material in which the preferredorientation of the nickel crystal by X-ray diffraction is (111) towardsthe electroforming deposition direction. Such a contact probe has therequired hardness and elasticity even when used under high temperature.

[0011] According to another aspect of the present invention, a contactprobe is fabricated by forming a resin mold with a cavity on a substratehaving conductivity, and filling the cavity with metal throughelectroforming. The metal includes a cobalt-tungsten alloy. By employingsuch a configuration, the abrasion resistance and heat resistance can beimproved. The same applies by using a cobalt-molybdenum alloy ornickel-molybdenum alloy instead of the cobalt-tungsten alloy. Also, acontact probe coated with any of said three types of alloys on thesurface can be used even if the interior is formed of another metal.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a perspective view of a contact probe according to afirst embodiment of the present invention.

[0013]FIG. 2 is a diagram to describe the contact probe according to thefirst embodiment of the present invention in a usage status.

[0014]FIG. 3 is a sectional view of the contact probe according to thefirst embodiment of the present invention corresponding to a fabricationmethod of a resist formation step and an exposure step.

[0015]FIG. 4 is a sectional view of the contact probe according to thefirst embodiment of the present invention corresponding to a fabricationmethod of a resist removal step.

[0016]FIG. 5 is a sectional view of the contact probe according to thefirst embodiment of the present invention corresponding to a fabricationmethod of a step of forming a metal layer on a resin mold.

[0017]FIG. 6 is a sectional view of the contact probe according to thefirst embodiment of the present invention corresponding to a fabricationmethod after the resin mold is ground.

[0018]FIG. 7 is a sectional view of the contact probe according to thefirst embodiment of the present invention corresponding to a fabricationmethod after the resin mold is removed.

[0019]FIG. 8 is a sectional view of the contact probe according to thefirst embodiment of the present invention.

[0020]FIG. 9 is a sectional view of the contact probe according to thefirst embodiment of the present invention corresponding to a fabricationmethod of a formation step of a resin body.

[0021]FIG. 10 is a sectional view of the contact probe according to thefirst embodiment of the present invention corresponding to a fabricationmethod of a resin body.

[0022]FIG. 11 is a sectional view of the contact probe according to thefirst embodiment of the present invention corresponding to a fabricationmethod after the resin body is ground.

[0023]FIG. 12 is a sectional view of the contact probe according to thefirst embodiment of the present invention corresponding to a fabricationmethod in the state where the resin body after being ground is attachedto the substrate.

[0024]FIG. 13 is a plan view an integral mask used in the evaluation ofthe contact probe according to the first embodiment of the presentinvention.

[0025]FIG. 14 is a chart representing the result of X-ray diffraction ona probe fabricated in Example 5 in the first embodiment of the presentinvention.

[0026]FIG. 15 is a perspective view of a contact probe according to asecond embodiment of the present invention.

[0027]FIG. 16 shows the contact probe according to the second embodimentof the present invention to describe the first step of a fabricationmethod thereof.

[0028]FIG. 17 shows the contact probe according to the second embodimentof the present invention to describe the second step of a fabricationmethod thereof.

[0029]FIG. 18 shows the contact probe according to the second embodimentof the present invention to describe the third step of a fabricationmethod thereof.

[0030]FIG. 19 shows the contact probe according to the second embodimentof the present invention to describe the fourth step of a fabricationmethod thereof.

[0031]FIG. 20 shows the contact probe according to the second embodimentof the present invention to describe the fifth step of a fabricationmethod thereof.

[0032]FIG. 21 shows a contact probe according to a seventh embodiment ofthe present invention corresponding to a first diagram to describe afabrication method thereof.

[0033]FIG. 22 shows a contact probe according to the seventh embodimentof the present invention corresponding to a second diagram to describe afabrication method thereof.

[0034]FIG. 23 shows a contact probe according to the seventh embodimentof the present invention corresponding to a third diagram to describe afabrication method thereof.

BEST MODES FOR CARRYING OUT THE INVENTION

[0035] (First Embodiment)

[0036] A contact probe 101 according to a first embodiment of thepresent invention includes, as shown in FIG. 1 by way of example, aplunger unit 1 to establish contact with a circuit to be tested, aspring unit 2 supporting plunger unit 1 at one end, and a lead lineconnection unit 3 electrically connecting the other end of spring unit 2with a lead line. Plunger unit 1, spring unit 2 and lead line connectionunit 3 are formed in one piece.

[0037] A probe card to which a contact probe is attached is configuredas shown in FIG. 2. A plurality of guide holes 22 are formed in aninsulation substrate 21 in accordance with the arrangement pitch of anunder-test circuit 25. A contact probe 101 is disposed in each guidehole 22. The leading end of each contact probe 101 protrudes from theplane of insulation substrate 21 facing an under-test substrate 24. Atthe other plane of insulation substrate 21 opposite to under-testsubstrate 24, a flexible printed circuit (FPC) 23 or the like identifiedas a lead line is disposed to be electrically connected to lead lineconnection unit 3 of each contact probe 101. Under-test circuit 25 is tobe tested using such a tester.

[0038] With regards to the performance required in such contact probesfor usage in a probe card, the inventors of the present inventionidentified the values set forth below. In order to generate sufficientload with a small spring mechanism, the Young's modulus is preferably atleast 180 GPa, and the elastic limit is preferably at least 1150 MPa,further preferably at least 1300 MPa. In order to exhibit abrasionresistance, the hardness is preferably at least 5000 N/mm², furtherpreferably at least 5800 N/mm². As to heat resistance, it is requiredthat these values are met under the usage of a high temperature up toapproximately 150° C.

[0039] The metal used as the material of the contact probe of thepresent invention is a nickel-manganese alloy. Although nickel (Ni)alone or a nickel type alloy such as Ni—Co or Ni—W can be thought of asthe material of the contact probe, metal not containing manganese isdisadvantageous in that sulfur brittleness is induced at hightemperature to become fragile, and heat resistance will be degraded.Such tendency of degradation in heat resistance is significant in therange of a high temperature of 200° C. and above. Although palladium(Pd), rhodium (Rh) or ruthenium (Ru) may be added to the metalidentified as the material of the contact probe, there will be thedrawback of the material cost being increased.

[0040] The amount of manganese contained in the nickel-manganese alloyis preferably at least 0.01% by weight and less than 0.3% by weight,further preferably at least 0.01% by weight and less than 0.15% byweight. If the amount of manganese is less than 0.01% by weight, theeffect of adding manganese is small, i.e., heat resistance is low. Ifthe amount of manganese is 0.3% by weight or above, the elastic limitcannot be maintained at a high level although heat resistance isachieved.

[0041] The nickel-manganese alloy can contain carbon from the standpointof increasing hardness. The amount of carbon contained in thenickel-manganese alloy is preferably not more than 0.02% by weight, morepreferably at least 0.001% by weight and not more than 0.02% by weight,and particularly preferably at least 0.001% by weight and not more than0.01% by weight. If the amount of carbon exceeds 0.02% by weight, theelastic limit is degraded.

[0042] The average crystal grain size of nickel in the nickel-manganesealloy must be not more than 70 nm, preferably not more than 50 nm. Ifthe average crystal grain size of nickel exceeds 70 nm, both the elasticlimit and hardness are degraded.

[0043] The preferred orientation of the nickel crystal in thenickel-manganese alloy by X-ray diffraction is (111) towards thedeposition direction liquid (surface direction) of the nickel-manganesealloy layer in electroforming. If the preferred orientation is not(111), the Young's modulus and elastic limit are so low that, whenfabricated into a contact probe, it will be difficult to generatesufficient load.

[0044] Fabrication Method of Contact Probe

[0045] A fabrication method of a contact probe includes the step offorming a mold for electroforming, the step of forming a metal layeronto the mold for electroforming, and the step of removing the mold forelectroforming.

[0046] The electroforming mold formation step can be conducted by alithography step, or a step using a framework such as a die.

[0047] The step by lithography includes a resist formation step, anexposure step, and a resist removal step. In the resist formation step,a resist film is formed on the surface of a substrate havingconductivity. As a substrate, a conductive substrate such as of SUS, Cu,Al and the like, or a substrate 30 as shown in FIG. 3, having the metalof Ti, Al, Cu or a combination thereof formed as a conductor layer 32 bysputtering on a substrate 31 made from Si, glass, or the like can beused. In the exposure step, an X-ray 35 is directed to resist film 33using a mask 34 corresponding to the configuration of the desiredcontact probe, as shown in FIG. 3. UV light may be used instead of X-ray35 in some cases. In the resist removal step, resist 33 of an exposureregion 36 is removed by development. As a result, a mold 51 forelectroforming is formed as shown in FIG. 4.

[0048] In the step of forming a mold for electroforming using a die,molding such as injection molding is conducted using a die 41 having aconvex portion as shown in FIG. 9 to form a resin mold 42 with a recessas shown in FIG. 10. Then, grinding is conducted to result in a resinpattern frame 43 with throughholes corresponding to the recess regions,as shown in FIG. 11. Resin pattern frame 43 is attached on substrate 30having conductivity, as shown in FIG. 12. For a substrate 30 havingconductivity, a substrate similar to that when a resin mold is to befabricated by lithography can be used. A conductive substrate such as ofSUS, Cu, Al and the like, or a substrate 30 having the metal of Ti, Al,Cu or a combination thereof formed as a conductor layer 32 by sputteringon a substrate 31 made from Si, glass, or the like can be used.

[0049] Following formation of a mold for electroforming, a metal layer37 is deposited on recess portion 38 (refer to FIG. 4) of a mold 51 forelectroforming as shown in FIG. 5 in the metal layer formation step.Metal layer 37 is deposited by electroforming. Electroforming refers toformation of a metal layer on a substrate using a metal solution. Then,grinding or polishing is conducted to attain a desired thickness.

[0050] In the step of removing the mold for electroforming, resist film33 on substrate 30 is removed by ashing using oxygen plasma or bydevelopment after irradiation through an X-ray or UV light. As a result,the configuration shown in FIG. 7 is obtained.

[0051] Then, only the portion of metal layer 37 is obtained bydissolving substrate 30 with potassium hydroxide (KOH), or by dryetching or the like. As a result, contact probe 101 as shown in FIG. 8is obtained. This corresponds to contact probe 101 shown in FIG. 1.

[0052] By the above steps in the fabrication method, a contact probehaving the plunger unit, spring unit and lead line connection unitformed integrally can be readily fabricated, accommodating the aspectsof microminiaturization and complexity of a contact probe. Furthermore,the assembly task is dispensable.

EXAMPLE

[0053] To obtain the manganese concentration and carbon concentrationshown in Tables 1-3 set forth afterwards, a solution having nickelsulfamic acid and manganese sulfamic acid blended was prepared, refinedby activated carbon, and then added with an anti-pit inhibitor and abrightener (including butynediol).

[0054] To evaluate the characteristics as a contact probe, a probe wasfabricated in accordance with the above-described contact probefabrication method. In the fabrication of a contact probe, a mold forelectroforming was formed by X-ray lithography on a resist applied on acopper plate sputtered with Ti, using a mask corresponding to a planarpattern as shown in FIG. 13. The thickness of all the probes was set to50 μm.

Examples 1-7

[0055] Alloys were prepared all having a nickel preferred orientation of(111) and a nickel average crystal grain size of 50 nm, differing onlyin the containing amount of manganese, as shown in Table 1. Probes werefabricated based on these alloys.

Comparative Example 1

[0056] A probe was fabricated with the features set similar to those ofExamples 1-7 with the exception that manganese is not contained.

Comparative Example 2

[0057] A probe was fabricated with the features set similar to those ofExample 4 with the exception that the average crystal grain size was 100nm.

Comparative Example 3

[0058] A probe was fabricated with the features set similar to those ofExample 4 with the exception that the preferred orientation was (200).

Comparative Example 4

[0059] A probe was fabricated with the features set similar to those ofExample 5 with the exception that the preferred orientation was (200).

[0060] Evaluation was conducted on the fabricated probes in accordancewith respective aspects set forth below.

[0061] Evaluation Mode

[0062] 1. Preferred Orientation

[0063] Evaluation was conducted through XRD (X-ray Diffractometry).

[0064] By way of example, the result of X-ray diffraction on a probefabricated in Example 5 is shown in FIG. 14. It is appreciated from FIG.14 that the probe had the preferred orientation of (111), the peakintensity ratio of (111) diffraction/(220) diffraction was at least 2,and the peak intensity ratio of (111) diffraction/(220) diffraction wasat least 5.

[0065] 2. Average Crystal Grain Size

[0066] The crystal grain size was obtained through the Willson schemeand Scherrer scheme based on the diffraction data obtained by XRD. Forverification, the crystal grain size was directly confirmed from a TEM(Transmission Electron Microscopy) image.

[0067] 3. Hardness

[0068] The hardness of the material was obtained by universal hardness(HU). The universal hardness was evaluated based on ISO Technical ReportTR14577 or DIN50359 using a sclerometer by Fischer Instruments K. K.

[0069] 4. Young's Modulus

[0070] The Young's modulus was measured using the aforementionedsclerometer. Also, the Young's modulus was obtained from aload-displacement curve by producing a specimen of H 0.05 mm×W 0.3 mm×L1 mm and conducting a bending test. Both measurements were calculatedwith the Poisson's ratio as 0.3.

[0071] 5. Elastic Limit

[0072] The elastic limit was obtained from the aforementioned bendingtest result for Young's modulus evaluation.

[0073] 6. Heat Resistance

[0074] A heat resistance test was conducted by measuring the Young'smodulus and elastic limit under the state where the sample wasmaintained at high temperature. The probe was rated as inferior when theYoung's modulus or elastic limit was degraded by at least 30%. Anysample fractured during testing was also rated as inferior.

[0075] The heat resistance was evaluated based on the followingcriteria.

[0076] ◯: Inferiority was not recognized in the measurements under 150°C. after being maintained at 150° C. for 10 days.

[0077] Δ: Inferiority was recognized in the measurements under 150° C.after being maintained at 150° C. for two days.

[0078] ×: The specimen was fractured during the measurement under 100°C. after being maintained at 100° C. for ten hours.

[0079] The evaluation results of the probes are shown in Table 1. Theparameters other than those in the column of heat resistance aremeasurements under room temperature. TABLE 1 Average Mn Crystal HardnessYoung's Elastic Concentration Preferred Grain (HU) Modulus Limit Heat wt% Orientation Size (nm) (N/mm²) (Gpa) (Mpa) Resistance Example 1 0.005(111) 50 5800 200 at least Δ 1300 Example 2 0.01 (111) 50 5800 210 atleast ◯ 1300 Example 3 0.05 (111) 50 5900 210 at least ◯ 1300 Example 40.1 (111) 50 5850 220 at least ◯ 1300 Example 5 0.15 (111) 50 5800 225at least ◯ 1300 Example 6 0.3 (111) 50 5600 225 1000 ◯ Example 7 0.4(111) 50 5450 230  800 ◯ Example 6 0.3 (111) 50 5600 225 1000 ◯Comparative 0 (111) 50 6000 220 at least X Example 1 1300 Comparative0.1 (111) 100 4700 200 1100 ◯ Example 2 Comparative 0.1 (200) 50 5050175  700 ◯ Example 3 Comparative 0.15 (200) 50 4500 170  750 ◯ Example 4

[0080] It is appreciated from the results of Examples 1-7 andComparative Example 1 that heat resistance is improved by the inclusionof manganese. It was identified that the concentration of manganese ispreferably at least 0.01% by weight from the standpoint of obtainingsufficient heat resistance. It was also found that, if the concentrationof manganese is 0.3% by weight or above, the elastic limit becomes 1000MPa or below. The elastic limit could not be maintained at a high level.

[0081] It was also appreciated from the comparison between the resultsof Example 4 and Comparative Example 3, or between Example 5 andComparative Example 4 that the hardness, the Young's modulus, and theelastic limit are all improved when the preferred orientation is (111)than in the cases where the preferred orientation is (200).

Examples 8 and 9

[0082] A probe was fabricated with the features set similar to those ofExample 4 with the exception that the average crystal grain size ofnickel in the nickel-manganese alloy was set to 30 nm and 70 nm,respectively.

[0083] The evaluation results of the obtained probes are shown in Table2, together with the results of Example 4 and Comparative Example 2.TABLE 2 Average Crystal Mn Grain Hardness Young's Elastic ConcentrationPreferred Size (HU) Modulus limit Heat wt % Orientation (nm) (N/mm²)(Gpa) (MPa) Resistance Example 8 0.1 (111) 30 5900 220 at least ◯ 1300Example 4 0.1 (111) 50 5800 220 at least ◯ 1300 Example 9 0.1 (111) 705150 200 1150 ◯ Comparative 0.1 (111) 100 4700 200 1100 ◯ Example 2

[0084] It is apparent from the results of Table 2 that the hardness andthe elastic limit become lower as the average crystal grain size ofnickel increases. It was identified that the average crystal grain sizeof nickel must be set to not more than 70 nm to achieve hardness greaterthan HU5000.

Examples 10-14

[0085] All probes were fabricated with 0.1% by weight as the manganeseconcentration and 50 nm as the average crystal grain size of nickel.Only the concentration of carbon in the nickel-manganese alloy wasaltered by adjusting the amount of butynediol that is an additive.

[0086] The evaluation results of the obtained probes are shown in Table3. TABLE 3 Average Mn C Crystal Hardness Young's Elastic ConcentrationConcentration Grain Size (HU) Modulus Limit Heat wt % wt % (nm) (N/mm²)(Gpa) (MPa) Resistance Example 10 0.1 0 50 5800 220 at least ◯ 1300Example 11 0.1 0.001 50 6000 210 at least ◯ 1300 Example 12 0.1 0.01 506300 230 at least ◯ 1300 Example 13 0.1 0.02 50 6600 225 1150 ◯ Example14 0.1 0.03 50 7000 230 700 ◯

[0087] It is appreciated from the results of Table 3 that the hardnessbecomes higher as the amount of carbon increases.

[0088] By using, as the material, a nickel-manganese alloy wherein thenickel average crystal grain size is not more than 70 nm and thepreferred orientation of the nickel crystal is (111) in accordance withthe present embodiment, a contact probe superior in the requiredcharacteristics such as elasticity, hardness and the like as well asheat resistance can be provided.

[0089] (Second Embodiment)

[0090] (Structure)

[0091] A contact probe 102 according to a second embodiment of thepresent invention is shown in FIG. 15. Contact probe 102 includes aplunger unit 1 to be brought into contact with an object to be tested, aspring unit 2 supporting plunger unit 1, and a lead line connection unit3 fixed at the tester side, all formed integrally by a cobalt-tungstenalloy. Contact probe 102 is configured with the planar pattern shown inFIG. 13, having a predetermined thickness.

[0092] (Fabrication Method)

[0093] A fabrication method of the contact probe of the secondembodiment according to the present invention will be described withreference to FIGS. 16-20.

[0094] As shown in FIG. 16, first a resist film 33 is formed on thesurface of a substrate 29 having conductivity. A metal substrate such asof SUS, Cu, Al, and the like can be used for substrate 29. Also, a Sisubstrate, a glass substrate, and the like can be used instead ofsubstrate 29. In this case, the metal of Ti, Al, Cu, or a combinationthereof is sputtered in advance on the top surface of the Si substrate,glass substrate, and the like to form an underlying conductive layer atthe surface.

[0095] As shown in FIG. 16, an X-ray 35 is directed onto the surface ofresist film 33 through mask 34. In the present embodiment, the method ofX-ray lithography is employed. Alternatively, the method of UVlithography using UV (ultraviolet ray) instead of an X-ray may beemployed. In either case, the resist of exposure portion 36 is removedafter development. As a result, a mold for electroforming 52 with arecess 38 is formed, as shown in FIG. 17.

[0096] As shown in FIG. 18, electroforming is conducted to fill recess38 with a metal layer 37 of a cobalt-tungsten alloy. This electroformingstep can be conducted with a metal-plating solution having cobaltsulfate, sodium tungstate, sodium gluconate, citric acid and otheradditives mixed appropriately. Then, the top surface is ground orpolished to be arranged to the desired thickness, as shown in FIG. 19.

[0097] Resist film 33 remaining on substrate 29 is removed by ashing orby development after re-irradiation. Substrate 29 is removed by etchingor the like. As a result, a unitary contact probe 102 can be obtained bytaking out metal layer 37 alone as shown in FIG. 20. Removal ofsubstrate 29 can be effected by both wet etching and dry etching.

[0098] (Function•Advantage)

[0099] The hardness of the contact probe fabricated as described abovewas measured using a Micro-Vickers hardness tester. The general contactprobe made from nickel or cobalt exhibits the hardness of 600 Hv at mostwhereas the contact probe of the present invention exhibits anappreciably high hardness of 720 Hv.

[0100] The contact probe was subjected to an abrasion test for 10000times by being urged against an aluminum plate for scribing. The amountof abrasion at the contact with the aluminum plate was measured. Theabrasion amount was 19% the abrasion amount of a nickel contact probe.

[0101] (Third Embodiment)

[0102] A contact probe is fabricated according to a fabrication methodsimilar to that of the second embodiment, provided that, in theelectroforming step of FIG. 18, recess 38 is filled with a metal layerof cobalt-molybdenum alloy instead of metal layer 37 formed ofcobalt-tungsten alloy. This electroforming step can be conducted with ametal-plating solution having cobalt sulfate, sodium molybdate, citricacid and other additives mixed appropriately. A contact probe of aconfiguration as shown in FIG. 15 was formed with a cobalt-molybdenumalloy, likewise the second embodiment.

[0103] (Function•Advantage)

[0104] The contact probe fabricated as described above was measuredusing a Micro-Vickers hardness tester, and exhibited the hardness of 700Hv.

[0105] The contact probe was subjected to an abrasion test similar tothat of the second embodiment. The measured amount of abrasion was 14%the abrasion amount of a nickel contact probe.

[0106] (Fourth Embodiment)

[0107] A contact probe was fabricated in accordance with the fabricationmethod of the second embodiment with the electroforming conditionaltered. The percentage content of tungsten in the cobalt-tungsten alloywas increased. It was confirmed that a crack was generated in thecontact probe when the percentage content of tungsten exceeds 25% byweight. Spring unit 2 cannot function as a spring. Therefore, it isdesirable that the percentage content of tungsten is greater than 0% byweight and not more than 25% by weight.

[0108] (Fifth Embodiment)

[0109] A probe was fabricated in accordance with the fabrication methodof the third embodiment with the electroforming condition altered. Theamount of molybdenum in the cobalt-molybdenum alloy was increased. Itwas confirmed that a crack was generated in the contact probe when thecontent of molybdenum exceeds 18% by weight. Spring unit 2 could notfunction as a spring. Therefore, it is desirable that the percentagecontent of molybdenum is greater than 0% by weight and not more than 18%by weight.

[0110] (Sixth Embodiment)

[0111] Two nickel contact probes were fabricated in accordance with thefabrication method of the second embodiment. These contact probesexhibited the measurement of 550 Hv in hardness. One of these contactprobes was coated with a 0.5 μm-thick film of cobalt-molybdenum alloy onits surface. An abrasion test similar to that of the second embodimentwas conducted on the contact probe with the coat film and the contactprobe without the coat film, and the amount of abrasion was measured.The amount of abrasion of the contact probe with the coat film was 35%the abrasion amount of the contact probe without the coat film. It istherefore appreciated that formation of a cobalt-molybdenum alloy filmon the surface serves to increase the abrasion resistance.

[0112] A similar effect can be achieved even if the coat film is ofcobalt-tungsten alloy. The metal used for the interior may be cobalt,copper, and the like in addition to nickel.

[0113] (Seventh Embodiment)

[0114] (Fabrication Method)

[0115] A fabrication method of a contact probe according to a seventhembodiment of the present invention will be described with reference toFIGS. 9-11, FIGS. 21-23, and FIG. 20.

[0116] As shown in FIG. 9, a resin mold 42 is formed by injectionmolding or the like using a die 41 having a convex configuration of acontact probe. As a result, resin mold 42 with a concave configurationcorresponding to that of a contact probe is obtained, as shown in FIG.10. Resin mold 42 is subjected to grinding to have the recess portionpierced. A resin pattern frame 43 as shown in FIG. 11 is obtained. Asubstrate 29 similar to that used in the second embodiment is prepared,and resin pattern frame 43 is attached thereon, as shown in FIG. 21. Asshown in FIG. 22, electroforming is conducted to fill recess 38 with ametal layer 37 of cobalt-tungsten alloy or cobalt-molybdenum alloy.Then, the top surface is ground or polished to be arranged to apredetermined thickness, as shown in FIG. 23.

[0117] Resin pattern frame 43 remaining on substrate 29 is removed byashing or by development after re-irradiation. Substrate 29 is removedby etching or the like. The removal of substrate 29 can be carried outthrough both wet etching and dry etching. As a result, contact probe 102shown in FIG. 20 is obtained by taking out only metal layer 37.

[0118] (Function•Advantage)

[0119] Through the above-described fabrication method, a contact probeof high abrasion resistance can be obtained by employing cobalt-tungstenalloy or cobalt-molybdenum alloy as the material.

[0120] A great difference in the percentage content of tungsten ormolybdenum between the plane of initiating electroforming and the planeof ending electroforming in the fabrication methods of the second andseventh embodiments will cause disproportion abrasion in the contactprobe. In order to suppress this problem of disproportion abrasion to anagreeable level, the difference in the percentage content between theplane of initiating electroforming and the plane of endingelectroforming is preferably within 25% of the percentage content at theplane of ending electroforming.

[0121] (Eighth Embodiment)

[0122] A contact probe is fabricated according to a fabrication methodsimilar to that of the second embodiment, provided that, in theelectroforming step of FIG. 18, recess 38 is filled with a metal layerof nickel-molybdenum alloy instead of metal layer 37 formed ofcobalt-tungsten alloy. This electroforming step can be conducted with ametal-plating solution having nickel sulfate, sodium molybdate, sodiumgluconate, citric acid and other additives mixed appropriately. As aresult, a contact probe of a configuration as shown in FIG. 15 wasformed with a nickel-molybdenum alloy.

[0123] (Function•Advantage)

[0124] The contact probe fabricated as described above was measuredusing a Micro-Vickers hardness tester, and exhibited the hardness of 700Hv. The general contact probe made from nickel or cobalt exhibits thehardness of 600 Hv whereas the contact probe of the present embodimentexhibits a higher hardness.

[0125] The contact probe was subjected to an abrasion test similar tothat of the second embodiment, and the abrasion amount was measured. Theabrasion amount was 20% the abrasion amount of a nickel contact probe.

[0126] A contact probe was fabricated in accordance with the abovefabrication method with the electroforming condition altered. Thepercentage content of molybdenum in the nickel-molybdenum alloy wasincreased. It was confirmed that a crack was generated in the contactprobe when the content of molybdenum exceeds 25% by weight, and springunit 2 cannot function as a spring. Therefore, it is desirable that thepercentage content of molybdenum is greater than 0% by weight and notmore than 25% by weight.

[0127] (Ninth Embodiment)

[0128] A contact probe is fabricated according to a fabrication methodsimilar to that of the seventh embodiment, provided that, in theelectroforming step of FIG. 22, recess 38 is filled with a metal layerof nickel-molybdenum alloy instead of metal layer 37 formed ofcobalt-tungsten alloy or cobalt-nickel-molybdenum alloy. As a result, acontact probe of a configuration as shown in FIG. 15 was formed with anickel-molybdenum alloy. A contact probe fabricated as described aboveoffers advantages similar to those of the eighth embodiment.

[0129] (Tenth Embodiment)

[0130] Likewise the sixth embodiment, a contact probe is coated with a0.5 μm-thick film of nickel-molybdenum alloy on its surface. An abrasiontest similar to that of the second embodiment was conducted on thecontact probe with the coat film and the contact probe without the coatfilm, and the amount of abrasion was measured. The amount of abrasion ofthe contact probe with the coat film was 38% the abrasion amount of thecontact probe without the coat film. It is therefore appreciated thatformation of a nickel-molybdenum alloy coat film on the surface servesto increase the abrasion resistance.

[0131] The metal used for the interior may be cobalt, copper, and thelike in addition to nickel.

[0132] (Eleventh Embodiment)

[0133] A contact probe of nickel-molybdenum alloy containing 20% byweight molybdenum was fabricated in accordance with the fabricationmethod of the eighth embodiment. The electrical resistance of thiscontact probe was measured. The electrical resistance of this contactprobe was 3.5Ω, which is approximately 7 times that of a nickel contactprobe. This contact probe made from nickel-molybdenum alloy wassubjected to a heat treatment of 300° C., whereby the metal crystal ofthe nickel-molybdenum alloy was partially rendered into ordered alloy.It is found that the electrical resistance is lowered to 0.6Ω, which issubstantially equal to that of a nickel contact probe. Also, thehardness which was 720 Hv in Vickers hardness prior to the heattreatment is increased to 780 Hv. The present embodiment is extremelypreferable in that the hardness of the contact probe is maintained atleast 600 Hv while the electrical resistance is suppressed to a levelequal to that of a nickel contact probe.

[0134] A great difference in the percentage content of molybdenumbetween the plane of initiating electroforming and the plane of endingelectroforming in the fabrication methods of the eighth and ninthembodiments will cause disproportion abrasion in the contact probe. Inorder to suppress this problem of disproportion abrasion to an agreeablelevel, the difference in the percentage content between the plane ofinitiating electroforming and the plane of ending electroforming ispreferably within 25% the percentage content at the plane of endingelectroforming.

INDUSTRIAL APPLICABILITY

[0135] The present invention is applicable to a contact probe for use toelectrically test a semiconductor IC chip, a liquid crystal display, andthe like.

1. A contact probe fabricated by forming a resin mold on a substratehaving conductivity, and filling a cavity of said resin mold with metalthrough electroforming, wherein said metal is a nickel-manganese alloy,and an average crystal grain size of nickel is not more than 70 nm, anda preferred orientation of a nickel crystal by X-ray diffraction is(111) towards a deposition direction of electroforming.
 2. The contactprobe according to claim 1, wherein said nickel has an average crystalgrain size of not more than 50 nm.
 3. The contact probe according toclaim 1, wherein said nickel-manganese alloy contains at least 0.01% byweight and less than 0.3% by weight manganese.
 4. The contact probeaccording to claim 1, wherein said nickel-manganese alloy containscarbon.
 5. The contact probe according to claim 4, wherein saidnickel-manganese alloy contains not more than 0.02% by weight carbon. 6.A contact probe fabricated by forming a resin mold with a cavity on asubstrate having conductivity, and filling said cavity with metalthrough electroforming, wherein said metal is an alloy for a probeselected from the group consisting of a cobalt-tungsten alloy,cobalt-molybdenum alloy, and nickel-molybdenum alloy.
 7. The contactprobe according to claim 6, wherein said alloy of the probe is acobalt-tungsten alloy, and a percentage content of tungsten is greaterthan 0% by weight and 25% by weight at most.
 8. The contact probeaccording to claim 6, wherein said alloy of the probe is acobalt-tungsten alloy, and a difference of the tungsten content of aportion formed by electroforming between an electroforming initiatingplane and an electroforming ending plane is within 25% of said contentat said ending plane.
 9. The contact probe according to claim 6, whereinsaid alloy of the probe is a cobalt-molybdenum alloy, and a percentagecontent of molybdenum is greater than 0% by weight and 18% by weight atmost.
 10. The contact probe according to claim 6, wherein said alloy ofthe probe is a cobalt-molybdenum tungsten alloy, and a difference of themolybdenum content of a portion formed by said electroforming between anelectroforming initiating plane and an electroforming ending plane iswithin 25% of said content at said ending plane.
 11. The contact probeaccording to claim 6, wherein said alloy of the probe is anickel-molybdenum alloy, and a percentage content of molybdenum isgreater than 0% by weight and 25% by weight at most.
 12. The contactprobe according to claim 6, wherein said alloy of the probe is anickel-molybdenum tungsten alloy, and a difference of the molybdenumcontent of a portion formed by said electroforming between anelectroforming initiating plane and a an electroforming ending plane iswithin 25% of said content at said ending plane.
 13. The contact probeaccording to claim 6, wherein said alloy of the probe is anickel-molybdenum alloy, and at least a portion of a metal crystal ofsaid nickel-molybdenum alloy is rendered into ordered alloy by heattreatment.
 14. A contact probe fabricated by forming a resin mold with acavity on a substrate having conductivity, and filling said cavity withmetal through electroforming, wherein a coat film of at least any alloyselected from the group consisting of a cobalt-tungsten alloy,cobalt-molybdenum alloy and nickel-molybdenum alloy is applied at asurface.
 15. The contact probe according to claim 14, wherein said metalincludes a material selected from the group consisting of nickel, cobaltand copper.